(1) Field of the Invention
The present invention relates to an isolation process of 2-chloroethyl vinyl ether which is useful for the raw material of various functional polymers.
(2) Description of the Prior Art
U.S. Pat. No. 3,023,250 discloses the process in which 1,1-di(2-chloroethoxy)ethane (hereinafter, called as CEE.) is decomposed thermally in the presence of an acidic catalyst, followed immediately by the conversion to an alkalinic reaction condition, and resulting in production of 2-chloroethyl vinyl ether (hereinafter, called as CEVE.).
In the above patent, CEE is decomposed in the presence of an acidic catalyst according to the formula shown below, ##STR1## to CEVE and 2-chloroethanol (hereinafter, called as CE.) but, if the decomposition is continued under an acidic circumstance due to the hydrogen chloride in the decomposition gas or an acid catalyst, the reverse reaction in which CEVE with CE returns to CEE or the polymerization reaction of CEVE itself proceeds dominantly. As a result, CEVE can be scarcely produced. Further, the patent suggests that such a base as an amine shall be employed immediately in the decomposition mixture to avoid the phenomenon. Namely, both the decomposition reaction and the recombination reaction are suggested to proceed at the same time at an elevated temperature in this reaction system.
As is shown in the above reaction scheme, the product, CEVE, the unreacted CEE and an equivalent mol. of the by-produced CE to CEVE exist in the decomposition mixture. But, the complete separation of CEVE from CE by a few distillations is actually impossible because CEVE distills azeotropically with CE. So, the above U.S. patent proposes that the azeotrope shall be washed with water, water-soluble CE shall be transferred to the water layer and the crude CEVE shall be dried and purified by distillation.
However, much water in the washing shall be dumped as waste water, and, further, because of the extreme difficulty in the recovery of CE mingled in the water layer, an uneconomic desertation of the CE occurs. These are serious disadvantages in the prior art.
If the CE existing in the aforementioned azeotrope can be changed to a raw material relating to the present process without the separation from the azeotrope, all of the by-produced CE can be utilized in a skillful manner.